let b = Buffer.from('abccc-=-dddder-=-qwerqwer');

Buffer.prototype.split = Buffer.prototype.split || function (b) {
  let arr = [];

  let cur = 0;
  let n = 0;
  while ((n = this.indexOf(b, cur)) != -1) {
    arr.push(this.slice(cur, n));
    cur = n + b.length;
  }

  arr.push(this.slice(cur));

  return arr;
};

let arr = b.split('-=-');
console.log(arr);

console.log(arr.map(buffer => buffer.toString()));
